Dell S4048T, Configuration Manual

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Configure a DCBx Operation
DCB devices use data center bridging exchange protocol (DCBx) to exchange configuration information with
directly connected peers using the link layer discovery protocol (LLDP) protocol.
DCBx can detect the misconfiguration of a peer DCB device, and optionally, configure peer DCB devices with
DCB feature settings to ensure consistent operation in a data center network.
DCBx is a prerequisite for using DCB features, such as priority-based flow control (PFC) and enhanced traffic
selection (ETS), to exchange link-level configurations in a converged Ethernet environment. DCBx is also
deployed in topologies that support lossless operation for FCoE or iSCSI traffic. In these scenarios, all network
devices are DCBx-enabled (DCBx is enabled end-to-end). For more information about how these features are
implemented and used, refer to:
• Configure Enhanced Transmission Selection
DCBx supports the following versions: CIN, CEE, and IEEE2.5.
Prerequisite: For DCBx, enable LLDP on all DCB devices.
DCBx Operation
DCBx performs the following operations:
• Discovers DCB configuration (such as PFC and ETS) in a peer device.
• Detects DCB mis-configuration in a peer device; that is, when DCB features are not compatibly
configured on a peer device and the local switch. Mis-configuration detection is feature-specific
because some DCB features support asymmetric configuration.
• Reconfigures a peer device with the DCB configuration from its configuration source if the peer device
is willing to accept configuration.
• Accepts the DCB configuration from a peer if a DCBx port is in “willing” mode to accept a peer’s DCB
settings and then internally propagates the received DCB configuration to its peer ports.
DCBx Port Roles
To enable the auto-configuration of DCBx-enabled ports and propagate DCB configurations learned from
peer DCBx devices internally to other switch ports, use the following DCBx port roles.
Auto-upstream The port advertises its own configuration to DCBx peers and is willing to receive peer
configuration. The port also propagates its configuration to other ports on the switch.
The first auto-upstream that is capable of receiving a peer configuration is elected as
the configuration source. The elected configuration source then internally propagates
the configuration to other auto-upstream and auto-downstream ports. A port that
receives an internally propagated configuration overwrites its local configuration with
the new parameter values. When an auto-upstream port (besides the configuration
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